This invention concerns a textile machine shut-off device, that is to say a device for switching off an individual electric-motor spindle drive of the machine when material being worked on the machine is interrupted, and more particularly a spinning or twisting machine incorporating comparator means for sensing the interruption of the material and a switch operative thereby to switch off the machine.
In the art it is already known to provide an individual electric motor spindle drive with a comparator arrangement to compare electro-magnetic forces derived from the current drawn from the mains by the motor with an adjustable electro-magnetic counterflow as a reference, the comparator including a switch-off device to stop the motor upon interruption of the material being treated. If in the textile machine, which is, for example, a spinning or twisting machine in which thread is wound on cops, a break should occur in the thread, the comparator operates to switch off the electric motor spindle drive. Disadvantageous in this known arrangement is the fact that only stopping of the single spindle drive is achieved. The remaining components of the textile machine, associated with the spindle and its drive, can continue to run independently.
Furthermore, already known in the art, in spinning machines, are devices for halting the roving for each spindle, if the thread breaks. In one such arrangement, at the exit of a drafting roller arrangement, the thread is guided by a rolling rod which, when the thread breaks, presses a wedge into a wedge-shaped hollow space through which the roving runs so that the roving is arrested. Disadvantageous with this known arrangement is that a threadsensing device must be provided which engages the thread and hinders the free running of the thread, particularly its movement in the so-called "spinning triangle".
Also known in the art is a process for supervising the working characteristics of a twisting and spinning machine having a number of spindles working simultaneously and disposed besides each other. This arrangement serves to sense deviations from normal working, particularly thread breakage, at each individual spindle and permits statistical determination of when and in which spinning location thread breakage occurs. This device too requires a special sensor which senses and reports thread breakage or the stopping of a spindle.
In contrast hereto, an object of the present invention is to provide a device of the kind referred to in the introduction hereto which can be constructed in such a way as to provide a comprehensive evaluation of a notification once obtained of an interruption in the working of a textile machine, particularly of a spinning or twisting machine, whereby, in particular, the thread is not damaged, which is important particularly with respect to very fine or very sensitive threads.